LISTFILTER was doubling delimiters on output.

(closes issue #16900)
 Reported by: bluecrow76
 Patches: 
       asterisk-1.6.2.4-func_strings.diff uploaded by bluecrow76 (license 270)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@251678 65c4cc65-6c06-0410-ace0-fbb531ad65f3

funcs/func_strings.c

@@ -405,7 +405,7 @@ static int listfilter(struct ast_channel *chan, const char *cmd, char *parse, ch
 				ast_str_append(&result, 0, "%s", delim);
 			}
 
-			ast_str_append_substr(&result, 0, begin, cur - begin + 1);
+			ast_str_append_substr(&result, 0, begin, cur - begin);
 			first = 0;
 			begin = cur + dlen;
 		}